Since a fine and precise surface is required for a substrate that is used for a semiconductor device or a display device requiring a high degree of integration, various planarization methods are applied. Particularly, due to the trend of high integration and high performance of the semiconductor device or display device, a method of polishing while relatively moving a polishing pad and a subject to be polished, while supplying a slurry composition including polishing particles and various chemical ingredients between the polishing pad and the subject to be polished, is generally used. In this polishing method, for more precise polishing, the subject to be polished is fixed on a mounting pad so as to maintain a constant location and position during the polishing or processing process.
However, a previously known mounting pad has internal pores of different sizes and the distribution of the pores is irregular, and thus the cushion property and adsorption to a subject to be polished is not good. Further, a subject to be polished cannot securely contact a mounting pad during a polishing process, and thus precise polishing may not be achieved. In addition, since a previous mounting pad exhibits non-uniform size and distribution of internal pores, the properties such as compressibility and compression recovery rate are not good and water repellency is not sufficient, and thus a subject to be polished does not have uniform contact during a polishing or processing process.